Predicted stop demand



July 12, 1960 J. E. MAGEE 2,944,634

PREDICTED STOP DEMAND Nra SET FCI-'a F; G JOHN EDM/QED MAGEE INVENTOR BY Q/Q ATTORNEY `Iuly 12, 1960 J. E. MAGEE 2,944,634

PREDICTED STOP DEMAND Filed July 24, 1959 '7 Sheets-Sheet 2 Jan/N Eon/4R0 M4455 1 N VE N To R BY ATTORNEY July l2, 1960 J. E. MAGEE 2,944,634

PREDICTED STOP DEMAND Filed July 24 1959 7 sheets-sheet :s

Ppp/ W/a 5pm 50m 597C P06/7a Puf/7b P007; -u' 51 7m 2K b P054 PUBb Pl/Bc JOHNEDWRD /V/AGEE INVENTOR BY ATTORNEY July 12, 1960 J. E. MAGEE 2,944,634

PREDICTED STOP DEMAND Filed July 24, 1959 7 Sheets-Sher(l 4 .JOHN EDM/#P0 MHGEE INVENTOR BY ATTORNEY July l2, 1960 Filed July 24, 1959 J. E. MAGEE PREDICTED STOP DEMAND 7 Sheets-Sheet 5 BYQ% ATTORNEY J. E. MAGEE PREDICTED STOP DEMAND July l2, 1960 7 Sheets-Sheet 6 Filed July 24, 1959 United States Patent ,l

The invention .relates to dispatching and control systems for a plurality of elevators operating as a group. It'is desirable in modern day elevator installations to control the operation of a group of elevators in such manner that, during periods of interim traliic, the elevator cars arrive at each'landing at predetermined spaced intervals. Furthermore, it is desirable to vary these spaced intervals in accordance with the number of cars in service and the existing actual demand for service. It is also beneficial to operate the elevator cars so as to give greater service in a given direction of travel when the demand in'such direction is greater. e

The invention involves accomplishing the foregoing by'eifecting the dispatching and control of each individual car in response to variations in actual registered demand and anticipated demand'ahead of it. With this arrangement, transient peaks of actual registered demand affect only one car of the group and provide an immediate response to such demand without disrupting group operation. lf a peak condition persists beyond the transient stage, other cars respond, as needed. Such a system provides eiiicient service for interim traiiic conditions, accommodates slight variations :in demand, and responds quickly to transient peak traiiic conditions. Furthermore, such a system has a relatively high operating eiiiciency and is extremely flexible.

It is therefore an object of the invention to provide a dispatching and control system for a group of elevators in which the response of the cars to demands for service at the landings is on an individual car basis in accordance with the combined anticipated and registered demand to which each car is subject.

In carrying out the invention according to the preferred embodiment, a predicted demand factor is established for each direction of travel from each landing of a building. This predicted demand factor is determined in accordance with the service characteristics of the tenancy of that landing and the type of service required by such tenancy and is utilized as part of the total demand to effect dispatching of the cars. Registered landing calls are also a part of the total demand. The predicted demand and registered demand are totalized up to the position of the car next preceding the one selected as next to be dispatched. When such totalized demand reaches a predetermined amount for the particular installation, the selected car is dispatched. In this manner, the system tends to serve each landing with regularity according to its anticipated needs, which regularity is automatically modied by the registration of demand at the landings. The removal or addition of a car from group operation automatically changes the amount of totalized demand utilized to effect the dispatching of a car.

In accordince with the arrangement illustrated, a certa-in portion of the registered and predicted demand ahead of the next preceding car may be added to the totalized predicted and registered demand behind that car to determine when the selected car is dispatched.

YCar calls in the selected car are preferably included as 2,944,634 Patented .iuiy 12, lt)

ice

registered demand affecting that car, but it ispreferred to limit their effect in each car to one call. In this manner the registration of more than one car call in the selected car cannot unduly affect its dispatching and thereby obviates the effect of passenger manipulation of the control system by the registration of false car calls.

A next preceding car, when it is carrying a certain load, automatically bypasses landing calls and is disregarded in the measurement of the registered and predicted demand, and the car ahead of it is regarded as the next preceding car in making this measurement.

In the absence of a selected car at the upper dispatching landing when sutlcient totalized demand exists for dispatching a car downward from that landing, an up traveling car which has entered a top selection zone is selected for down dispatching and such car is caused to reverse at the landing of its highest` call or at the bottom of the top selection zone, whichever is higher, and be dispatched downward.

If a car call is registered in the'selected car at the upper or lower dispatching landing for a certain period, the car is immediately dispatched. Also, if a selected car at the lower dispatching landing becomes loaded to a certain percentage of capacity, it is immediately dispatched.

A selected car at the lower dispatching landing is preordained to reverse at its highest call under conditions where it has a car call registered for a certain period or becomes loaded to a certain percentage of its capacity, provided that, in each case, when such condition arises, all previously existing landing calls have been answered for at least a certain time and any landing call registered subsequent to that time has not been registered for at least a certain period.

Features and advantages of the invention will be seen from the above, from the following description of the operation of the preferred embodiment when considered in conjunction withthe drawings and from the appended claims.

In the drawings:

Figure l is a simplified schematic wiring diagram of a portion of the elevator power and control circuits for one car of the group, including car call registration circuits, car call pickup and canceling circuits, car call above circuits, and slowdown and stop initiating circuits;

Figure 2 is a simplified schematic wiring diagram of another portion of the elevator control circuits and landing call pickup and canceling circuits for one car of the group, along with landing call registration circuits, landing call above circuits, and landing call in registration circuits common to all cars of the group;

Figure 3 is a simpliiied schematic wiring diagram of car availability circuits, car selecting circuits, dispatching circuits, and car position and direction sensing circuits for the group;

Figure 4 is a simplified schematic wiring diagram of predicted and registered demand totalizing circuits;

Figure 5 is a simplified schematic wiring diagram of preordained highest call reversal circuits;

Figure 6 is a simplified wiring diagram of car position and direction indicating circuits common to the cars; and

Figures 7 and 8 are spindle sheets for use in side-by-side alignment with Figures 1 through 6 for locating the coils and contacts in Figures l through 6, the number of the figure in which a particular coil or pair of contacts appears being appended, following a dash, to the particular designation for that coil or pair of contacts.

The invention will be described, for convenience, as a control and Vdispatching system for a three car group of elevators serving l7 landings, designated 1 through 17. In the arrangement illustrated the lst landing is the lower dispatching landing, and the 17th landing is the upper dispatching landing. It willl be understood that the prinf ciples of the invention are equally applicable to elevator installations having different numbers of landlngs, different numbers of cars and ditlerent landings utilized as dispatching landings.

The circuits for some of the intermediaitclandngs have been omitted, for the sake of brevity, and it is. to be understood that the circuits for such intermediate landings are intended to be similar to those illustrated for other intermediate landings.

For the sake of brevity, the power and control circuits for the car and hoistway doors have not been shown, it being understood that they areof the conventional automatic door opening and closing type.

Differentiation will be made between the different ele.- vators by appending to the characters, employed to designate the various elements of the. system, lower case letters af b and 'c, indicative of the different elevators.

The electromagnetic switches employed in the system illustrated are designated. as follows:

BLD-Down landing call switch BLTe-Landing call time switch BLU-,Up landing call switch CKB-Up selected car, car call switch CKT-Down selected car, car call switch CS-Car in service switch DN-Down direction switch H-Field and brake switch HCC--Highest car vcall switch HID-Highest down landing call switch HJU-Highest up landing call switch LDW-Up selected car load switch NS-Non-stop switch NT-Time delay switch PDD-summation down demand switch PDU-summation up demand switch PHC-Preordained highest call reversalswitch 2PID-17'PID-Down car position switches 1PIU-16PIU-Up car position switches S11-Starting and slowdownswitch SS-Stopping switch UP-Up direction switch VB-Available up car switch VDR-Down notching switch VT-Available down car switch VUR-Up notching switch WB-Up selected car switch WBX-Up dispatched holding switch WT-Down selectedy car switch WTX-AuXiliary down selected car switch XC-Car call pick-up switch XH-Car reversal switch XS-Landing call pick-up switch ZK-Car call time switch In the wiring diagrams, the foregoing identifying letters are applied to the coils of the electromagnetic switchesr and, with reference numerals appended thereto, are applied to the contacts of the switches tol differentiate between different sets of contacts on the same switch, all contacts being shown for theunoperated condition of the switches. The numerical prefix designations of switches PID and PIU indicate the landings with which these switches are associated. Switches SR, DN and UP which are latching switches, eachI have two coils, one an loperating coil and the other a reset coil and are shown inreset condition.

Switches VDR and VUR (Figure 3)are rotary stepping switches utilized in the selection of cars for dispatching. Switch VDR is provided for the upper dispatching landing and switch VUR for'the lower dispatching landing. series of stationary contacts, one for each car, and preferably three rotary brushes positioned approximately120 apart and adapted successively to engage the stationary contacts. These brushes, designated VDRB and V-URB Each stepping switch is provided with aV l and differentiated by numbers, are rotated counterclockwise in step-by-step movement by their respective operating coils VDR and VUR. The contacts engaged by the brushes are designated VDR and VUR. Successive deenergization of operating coils VDR and VUR to cause stepping operation is effected by contacts VDRl and VURl, respectively.

Manually operated switches are designated ES, KSl, KS2, SB, KSD and. KSU.

In Figure l, for simplicity, the circuits which are individual to each car are shown only for cara, it being understood that like circuits are provided for lcars b and c. Car 2 connected to couoterweight. 3 is raised or lowered by means of hoisting roping 4 passing over sheave 5 mounted on shaft 6 of hoisting mechanism. The hoisting mechanism consists of a direct current hoisting motor having an armature MAa supplied with current at a vari- -able voltage from a generator armature GA@ which is rotated by a driving motor. (not shown). The hoisting.

motor has. a separately excited field winding designated MF4. The generator has. a series field winding designated GSFa and. a. separately excited eld winding GI-`a-.

Starting and slowdown switch- SRa controls the strengthV of the generator separately .excited eld winding GFa.

by means of resistor RCFcz, provided in the separately excited generator eld circuit to eifect deceleration ot" the car. BRa designates the release coil of the. electromagnetic brake.

Mechanism actuated in accordancel with movement of the elevator car is utilized in the circuits for each elevator.

Such mechanism, may bein the form of a conventional` selector machine as described in connection with Figure 2 of the Glaser and Hornung Patent No. 2,589,242, but.

considerably simplified in accordance with the simplied circuits herein disclosed.

Shown in the wiring diagrams are the following brushes.

Y and the stationary` contacts with which they cooperate:

For convenience, and as part of the simplication, it will be assumed that the selector machine is provided, only with the synchronous panel and that brushes are carriedby this panel in position to engage their corresponding4 stationary contacts which are mounted'on floor bars on; the selector. The brushes. are shown for the condition in which all cars are at the lowerdispatehing landing,

Brushes designated BCB (Figure l), BUHH, BDHHV (Figure 2V), PUB and PDB (Figure, 3) are cOnStructcd So.

as to span momentarily two of their successive stationary: contacts in traveling from one suchr contact to the next one. Brushes BU, BD, CPBU and CPBD (Figure l) are` positionedA so as to engage their respective stationary contactsa predetermined slowdownA distance ahead of the car with which they are associated. arriving at ther landing. Brushes UPB and DPB (Figurel) are of thev elongated type, adapted to engage their respective, staf` tionary contacts slightly before brushes BU and BDv engage their respective stationary contacts. Brush pairs` BPU, ZBPU yand BPD and ZBPD, (Figurelf) are. soposif.4 tioned that the one brush of each .pair isin phasepositiong with its associated car and the other brushy is one landing behind, and each brush in each pair is constructed so-asfto span momentarily two of its associated successive stationary contacts in traveling from one such contact to .the next one.

Main landing switch MLa and top landing switch TLa (Figure 1) are actuated by car movement las the car arrives at the lower dispatching landing and upper dispatching landing, respectively, their contacts being shown for the condition of car a parked at the lower dispatching landing. Hoistway door switchv DCOa and car door switchGIa (Figure 1) are actuated by rdoor movement;

their contacts being shown for the closedcondition of the doors. Load switch LSa (Figure 2). and load dispatch switch LDSa (Figure 5)`r may be. microswitches located under the car platform in the conventional manner to be actuated by load in the. car. Forpurposes of this embodiment, switch LSa is preset to be actuated when the load in the car is say 80% fofv capacity and switch LDSa is actuated-*when the load yattains say 50% of capacity, both switches being shown in unactuated condition.

Referring to Figure 2, up landing call buttons are designated UH and down landing call buttons are designated DH, numerals being appended for indicating the landing for which the buttons are provided. Each of these landing call buttons UH and DH comprises a gas tube and a xed button TB connected to the tube envelope with the circuits arranged so that the tube conducts inresponse to the touch of a nger on the button TB and remains conducting, thereby registering the call'and enabling the touch to be discontinued. The primary of transformer TF may be supplied with alternating current from any suitable source to provide alternating current for thegasy tube tiring circuits and, over line AC1?, to provide half wave rectified current for the automatic vlanding call cancelling circuits to extinguish the tubes. and operation of the landing call registering circuits and automatic landing call cancelling circuits are more fullyl disclosed and described in the aforementioned Glaser and Hornung patent. f

Transformer TF of Figure 2 likewise provides alternating current and half wave rectified current for the car call registrationand cancelling circuits of Figure l. Car call buttons are designated C and, as in the case of the landing call buttons UH and DH, have numerals appended thereto, indicative of the landing for which the car call buttons are provided. Each of these car call buttons C comprises a gas tube and fixed button TB of like construction `and operation to landing call buttons UH and DH. A touch of a inger on iixed button TB by a passenger in the elevator car causes the tube to conduct and remain conducting, thereby registering the car call and enabling the touch to be discontinued. Tube TV, which relates to the control of the extent of upward travel of the cars, is of a gas diode type, which maintains a constant voltage drop across its anode-cathode electrodes. These car button circuits are shown only for car a, it being understood that they are the same for the other cars.

Although, for the sake of brevity, the highest landing 'call circuits, landing call pickup circuits and automatic landing call cancelling circuits (Figure 2) have been shown only for car a, likeV circuits are provided for each of the elevators of the group by interconnection of the selectors for each elevator, as indicated by cross-connecting wires WU, WD, WHU andWHD for the variousv landings. Interconnecting wires WUV and WD also crossconnect the landing call registering circuits of Figure 2 with thedernand totalizer circuits of Figure 4. The car call registering circuits for each elevator are interconnected to the circuits of Figure 5` by cross-connectingl wires WC. The cathode electrode CD of diode TV is interconnected to the car call registering circuits (not shown) of the other elevators of the group by cross-connecting wire W65.

Shown in Figure 4 are the circuits for totalizing the predicted and-registered demand for the Vcar selected for The structure up dispatching and that for the car selected for down disi patching. This registered and predicted demand for convenience is expressed lin units of basic demand. Reisistors, which will be termed demand resistors, are utilized for this purpose and are connected in parallel in the totalizing circuits to totalize the demand units to which a selected car is subject. The demand due to car calls registered for a car which isv selected is totalized in the up demand totalizing circuit by means of car call demand resistors RKBa-c and in thew down demand totalizing circuit by means lof car call demand resistors RCKa-c. The demand due to registered landing calls is totalized in the up demand totalizing circuit by means of up landing call demand resistors ZRUR through 16RUR .and down landing call demand resistor 1'7RDR and in the down demand totalizing circuit by means of down landing call demand resistors ZRDR through 16RDR and up landing call demand resistor IRUR; The predicted demand established for each landing for each direction of travel is totalized in the up demand totalizing circuit by means of predicted up demand resistors ZPUR through 16PUR and predicted down demand resistor 17PDR and in the down demand totalizing circuit by means of predicted down demand resistors ZPDR through 16PDR and predicted up demand resistor IPUR. The numerical prefix designations of landing call demand resistors RUR, RDR and predicted demand resistors PUR, PDR, indicate the landings for which the respective resistors are provided.

' The ohmic value of each of thesedemand resistors is adjusted by positioning its adjustable tap in accordance with the weightY in demand units .to be given to the demand which it represents. The weight in demand units given .to carcdls registered for a car which is selected is preferably the same, regardless of the number of car calls registered. Relating these resistors to a one demand unit basis, a resistor having a weight of say tive demand units has an ohmic value of one fifth that of a resistor representing one demand unit. Also, fractional units maybe involved, as where say a resistor has a weight of one and three quarters demand units, in which case its ohmic value is four-sevenths that of a resistor representing one demand unit. When the total number of demand units to which the selected car is subject, represented by the ohmic values of the resistors connected in parallel in the totalizing circuit, reaches a certain amount, enough current flows in the totalizing circuit to eiect a dispatching operation for that car, as will be explained in more detail later.

The demand totalizer circuits for up dispatching include the triode tube PTU which, when the demand is low, conducts insuliicient current to operate summation up demand switch PDU. The amount of current flow through the tube is controlled by the potential applied to the grid of the tube. This in turn is determined by the position of adjustable tap T1 on resistor PDUR-1 which fixes the number of totalized up demand units for applying a value of positive potential on the grid to cause the tube to conduct suthcient current to operate switch PDU. Similarly, demand totalizer circuits for down dispatching include the triode tube PTD and the position of adjustable tapTl on resistor PDDRl determines the number of totalized down demand units for applying a value of positive potential on the grid of the tube to cause the tube to conduct sufficient current to operate switch PDD. Switches PDU and PDD act to initiate dispatching of selected cars, as will be explained later. The number of totalized demand units for causing dispatching of a selected car under condition where one car of the group is removed from group operation, is determined by the positions of adjustable taps T2 through T4 on resistors PDURI and PDDRI, as will be described.

It is to be understood that theA number of totalized demand units for dispatching a car, the weight established for the individual predicted demand factors and `for the car call and' landing call registered demand may vary in accordancewith the characteristics of each particular installation, Furthermore, they may be readjusted inra particular installation, as experience and changes in tenancy dictate. Also, if it isdesired for. a particular installation,` the predicted demand'v for a given direction of travelf'may be given more weightin establishing al demand for dispatching a selected car inthat direction than the weighfgiven tothe predicted demand; for dispatchingl a selectedu car in the-oppositeV direction. For example,

when an up trayelingcar stops in answer to a landing call,

the enteringpassenger usually registers arc'ar call. for-l; another landing, requiringfthat car to make a sect'. md1stopH before it reaches the upper-` dispatching landing. Whenl av down traveling car--stopsin answer tclanding calls, the entering passengers in.. many instances wish to travel directly to the lowerdispatching landing..- It therefore mayY be desirable to establish forA the landings agreater predicted' demand-in the updirection than in the downA direction.

Shown in Figure 6 are position indicating lamps designated LD and LU with numerals appended thereto, indicating the landings for which they are provided. The vertical row ofl lamps designated LD is provided for indicating the positions of cars traveling in the down di. rection, while the row of lamps designated LU is for in dicating the positions of cars traveling in the up direction.

The operation of" starting and stopping an elevator car` will rst be described. The circuits for controlling the starting and stopping ofcar. a are shown in Figures 1v and 2. Assume that car arisat the lower dispatching. terminal, set for uptravel with its car and hoistway doors closed, and that its dispatching has been initiated.v Under suchconditions up direction switch UPa is in operated condition, conditioning car aior. upward travel and up dispatch holding switch WBXa is in operated condition. Thus contacts WBXZa (Figure l) are engaged, completing a circuit for the operating coil of starting and slowdown switch SRa through manual switch KSZa and contacts NTSa. Switch SRa operates. to latch itself in operated condition. In doing. so, it engages contacts` SR4a, short circuiting a portion of resistance RCFaA in series with generator lield winding GFa. It also. engages contacts. SRSawhich,l since the doors are. in. closed position, cornplete a circuit through hoistway door switch contacts DCQa, car door switch contacts GIa and emergencys-Witch ESa for the coil of field andbrake-switch Ha.

Swith Ha operates to engage contacts H711 and H811. This completes a circuit for the release coil of brake BRa to release the brake. It also engages contacts Hlla and HlZa and separates contacts Hla, thereby energizing the generator eld, winding GFrz through contacts UPlOrz andy UPlin, causingl the car to start in the up di. rcction. In addition switch H01 engages contacts H9c1 (Figure 2), completing a circuit for the coil of time delay switch N11" a. Switch. Ha also `engages contacts H511 (Fignre l) tc. prepare a self holding circuit- As car a' starts upward, brush Brzleaves stationary contact CCla, interrupting the circuit for the coil of stopping switch SS'a. Switch .SSa releases, .engaging contacts S51@ to complete a holding circuit for switch Ha through oo ntacts H54. Also as car a leaves the lower dispatching landing. main landing switch MLa1 is actuated by cer movement.. closing its contacts MLM and opening its ccntacts MLza without eiect at this time.

Car ,a in traveling upward answers car calls and landing calls. Assume; that a passenger entered cnr a at the lower dispatching landing and registered a car call for the 3rd landing. Inl `such a case, tube -C3r1 (Figure l) is in conducting condition, establishing a potential drop across resistor RCM. As car r1 approaches the 3rd lande ing, brush CPBUa engagesstationary` contact CP311, completing a circuit for` the coil of car call pick-up switch XCa, the circuit extending.- from the left side of resistor RCSa bywayof stationary contact CP311, brush CPBUa,

8; contacts-UPM, coilv otswitch XCa, rectifier. REla and.r re; sistor R-la over. line B. to. the-right. side of resistor; RCSa.

Switch XCa operates to engage contacts XCZa, for purlf` poses to be explained.. Thisswitch-,also engagescontacts XCla, completingk a circuit for the release coil'of start-A ing` and; slowdown switch: SRal through contacts UPa and'thence through .brush BUa=in engagement with, sta.

tionaryn contact CCSa.

Switch.. SRa, upon releasing, engagescontacts. SRZ. Thisfcauses hal-fwave. rectiied voltage to, be applied to the cathode of tube. 03a, thereby extinguishing this tube tofcanel'; thezcar call, 'The cancellingv circuit extends. from transformer.y (Eigurefl'). through rectifier,r REA and over linel AC1 through contacts SRZa (Figure 1) XCZa',` rectifier RE2a,contactsf.U,B2t1 and brush CPBUa.

in engagement with stationary.. contacts CP3a. Switch SRa. alsolseparates contacts. SR4t1, inserting; resistor RCFa in.` series with generator.- field winding. GFa. to. effect slow: down ofcar a. This.l switch', also initiates, the. automatic. door opening operation (the circuits not being shown),

in a standard mannen- Y It: also. separates contacts S R3a,

but without effect, since they, are. short circuited by conf tacts HSa; and S5111.

switch Ha..

contacts. Hlla. and; H12@- tc disconnect generator field winding G1111,` from its,l Supply lines, causing the stopping otvthe car.

Winding? Syyiti` Hg also-separates its contacts H941 (FigureZ),

interrupting thecircnit for the coil of switch NTa. Switch. Ng'lfa iside/layed,y in releasing, bythe discharge of condensen Q through its coil,4 toestablish a predetermined passenger.

transfer time interval during which passengers may enter.v

or leave the car. After condenser Q. has discharged s uciently,. switch NTA-releases to initiate the automatic dem' closing cncraticn (the circuits thereof Het 'beine shown). It'alsoJ engages contacts NTa (Figure 1f) to..

complete a circuit for the operating` coil of switch Splitta,y throughrnainlaniing switch contacts lt/ILl'av and top landins `switch contacts 11.1@ SwitchV SR@ operates. and' latches in operated. cenditien, engaging contests SRii and, as the. decis reechclcsed position, completes e .cir-.Y

cuit forthe coil of' Switch Ha throughA contacts Gla and` DCOa thereby again starting car a upward, as has been, previously described.

Next assume that as. car a isy traveling upward, an up, landing call is registered. for the 15th landing. In such acasc, tube UHQS (Figure 2) is in conducting condition, establishing a voltage drop across resistor RUlS. As car 1 1 approachesthe 15th landing, brush UPB@` engages stationary contact UHISa, completing a circuit for the coil of landing cali pick-up switch XSa, the circuit ex-l tending from the left side of resistor RUlS through staticnaryA contact UHKlSla, brush UPBa, contacts UP4a, the coil of switch XSL?, rectifier REa, contacts NSla andrei-i, sistor R26; to line B, Switch XSa operates to. engage contactsr XSZa, preparing the landing call cancelling circuit, Switch K Srq alsoiengagcs contacts XSla (Figure 1),'con1f pleting a circuit through contacts UPSa 'and' brush BU@ in engageinentwith stationary contacts CClSa for the re-l lease-coil of switch SRa. Switch SRa releases to engage contacts Silla (Figure 2), thereby applying half-wave rectiiied voltage from transformer 'IF over line AC1: through contacts XSZqto the cathode of tube Ul-Il to extinguish the tube and cancel that landing call, Other up traveling cars. are. thus.. prevented from 1^ .S1 Qnfli11.g` t9. that landing call. Switch SRa separates vcontacts 5R41; (Figure 1). to effect slowdown of. the car and initiate the automatic opening of `the doors, as it approachesthq Switch H; also engagesr contacts Hloa to. establish a suicide. connection for. the generator field,I

aci-insa- 9 15th landing. As car a arrives at the 15th landing, brush Ba engages stationary contact CCISa, completing -a circuit for the coil of switch to stop the car, as has been previously described.

After the expiration of a passenger trans-fer time interval, established by condenser Q (Figure 2), the doors automatically close and car a continues upward. As the car approaches the upper dispatching landing, top land-v ing switch TLa is actuated by -car movement, closing contacts TL2a to complete a circuit for the 4release coil of Switch SRa. This switch releases to effect slowdown of the car. Switch TLa also opens contacts TLla, with# out effect. As the car arrives at the upper dispatching landing, brush Ba engages stationary contact CC17a, completing a circuit for the coil of switch S-Sa. This switch operates to stop the car, as has been previously described. Also, as the car arrives at the upper dispatching landing, brush BZa (Figure 2) engages stationary contact CTLa, completing a circuit through contacts DNGa and H6a for the release coil of switch UPa and the operating coil of switch DNa, thereby conditioning car a for downward travel. The dispatching of the car on its downward trip from the upper dispatching landing will be described later. As the car leaves the landing, top landing switch TLa is again actuated by lcar movement, reclosing contacts TLla (Figure l) and reopening contacts TLZa.

In a similar manner, as the car approaches the lower dispatching landing, main landing switch MLa `is actuated by car movement to open contacts MLla, but without eifect at this time. It also closes contacts MLZa, completing a 4circuit for the release coil of switch SRa to initiate slowdown of the car. As brush Ba engages stationary contact CCM, a circuit is completed for the coil of switch SSa to stop the car. Also, as the car arrives at the lower dispatching landing, brush BZa (Figure 2) engages stationary contact CMLa, completing a circuit through contacts UP9a and I-Ia for the release coil of switch DNa and the operating coil of switch UPa, thereby conditioning car a for upward travel.

It is to be noted that car a responds to car calls while traveling downward in the same manner as described for upward travel, brush CPB-Da picking up the calls instead of brush CPBUa. Similarly, landing Icalls are picked up during downward travel by brush DPBa (Figure 2) instead of brush UPBa, and the slowdown of the car during downward travel is initiated by means of brush BDa (Figure l) instead of brush BUa.

An understanding of the invention can best be gained from a description of the sequences of operations. Assume that for this particular installation the -demand for the selected car is measured as follows: one or more car calls registered in the selected car equals demand units, each registered landing call also equals 5 demand units, the predicted demand factor for each landing for each direction of travel is established as 1 demand unit except as follows: the predicted up demand factor for the lower dispatching landing is established as 4 demand units to provide a desirable preference in service to incoming traffic, the predicted down demand factor for the upper dispatchingv landing is established as 3 demand units to provide a parking preference for that landing, the predicted up demand factor for the 2nd and 3rd landings, each, is established as 2 demand units to give a slight preference to up traffic from these landings, as would be desirable, if for example, a cafeteria for building employees and a mailing room ywere located at the 2nd and 3rd landings, respectively, no predicted up demand factor is established for the upper dispatching landing, since there are no landings above, no predicted down demand factor is established for the lower dispatching landing, since for simplicity, landings below the dispatching landing are not considered in this example, and the predicted down demand factor for the 15th landing is established as 3 units `to give down traiiic lfrom that landing preference, as would be desirable, if for example, the tenancy car switch VBa.

of that landing comprises a rela-tively large number of people. As has been previously explained, the aforementioned registered and predicted demands are totalized in demand units by connecting resistors representative of these demands in parallel in the totalizing circuit for the selected car for the direction -to which the demands relate.

Next assume that the total registered and predicted demand for dispatching a selected car is established as say 15 demand units for each direction. In other words, with three cars in group operation, adjustable taps T1 are positioned on resistors PDURl and PDDRI so as to prevent each of tubes PTU and PTD from conducting sufficient current to initiate dispatching of a selected car until the totalized Idemand to which the selected car for the corresponding direction of dispatching is Subject reaches a total of 15 demand units. For each direction of travel, this occurs when the ohmic values of the demand resistors connected in parallel in the totalizing circuit for that direction are such that the resultant resistance provides the desired number of demand units.

Assume that cars a, b and c are at the lower dispatching landing and are set for upward travel. In such a case, as car av arrived at the lower dispatching landing traveling downward, brush BZa (Figure 2) engaged stationary contact CMLaA and, upon the engagement of contacts H6a during the stopping operation, a circuit was estab-lished by way of contacts UPa for the release coil of down direction switch DNa and for the operating coil of up direction switch UPc. This caused switch DNa to be reset and switch Ula to operate. Switch UPa latched into operated condition thereby setting car a for upward travel. Switch UPa also separated contacts UP9a, interrupting the circuit through its operating coil and the reset coil of switch DNa. Similar circuits (not shown) were established for cars b and c, as they arrived at the lower dispatching landing, thereby conditioning them for upward travel.

Next assume that cars a, b and c are put into group operation in that order by closing manual switches KSl to complete the circuits for the coils of car in service switches CS, the circuit for the coil of switch CSa for car a being shown in Figure 2. Switch CSa operates to engage contacts CS4a (Figure 3), complet-ing a circuit through contacts NSZa and UPSa and thence through -b-rush PUBa in engagement with stationary contact PUCla for the coil of up car position switch 1PIU. This switch operates to engage contacts lP-IUZ (Figure 6), thereby illuminating lamp1 LUl in the car position indicator panel to indicate that a car is at the lower dispatching landing yand is set for upward travel. Switch lPIUa also separates contacts lPlUl (Figure 4), for purposes to be explained later. It may be noted, that so long as any car of the group is at the lower dispatching landing and is set for upward travel, switch IPIU remains in operated condition, maintaining contacts 1PIU1 separated.

Switch CSa also engages contacts CSZa (Figure 3), completing a circuit through brush SDBa in engagement with stationary contact SDMa for the coil of available up Similarly, like circuits are completed by means of b-rush SDBb in engagement with stationary contact'SDMb for car b, and brush SDBc in engagement with stationary contact SDMc for car c for the coils of available up car switches VBb and VBC for cars b and c, respectively. Switch VBa operates to engage contacts VBZa, completing a circuit through rotary brush VURBI of up notching switch VUR, which brush is shown in engagement with stationary contact VURa, and through contacts WBXfla for the coil of up selected car switch WBa. Switch WBa operates to separate WBSa, preventing energization of the coil of switch VUR and thereby maintaining brush VURBI in engagement with stationary contact VURa. Thus, car a is selected as the next car to be dispatched upward,

In the absence of car calls registered inV selected car a'nd of` landing calls in registration, there is sufficient' tot izedy demand in the' system, underV the `assumed con d-it'ion's,` to cause car a to be dispatched upward, asf soon3 as' itis selected. Such demand is due solely to the suini# rtion f -tlie predicted up demand (previously de'- scribcd) establ-ished at the landings and is totalizedasflldv's' plurality of circuits is established though resistor PDURd (Figure 4), one such circuiti extendJ ingv fr'rriline B+ through predicted down demand r'esister IIP'DR?, representing t'lie predicted `demand from the `17th landing in the down direction, contacts 17PID1 and contacts IGPIUI through ZPIUgL contacts WBXSa, WBXSb, WBXS'C and resistor PDURl tol line B, similar circuits being completed through resistor" PDURI from iine`ii+ through predicted up demand resistors 1-6PUR to andV including ZPUR, representing the predicted rup demand from the 16th through 2nd landings respective- Iy.j Therefore, a total of t6 demandY resistors are conne'ot'ed in parallel with each other and in series with resistor PDU-R1, providing' for the weights in demand units` previously assigned in this example to the foregoing' predicted demand resistors a total of 20 demand units'. Since it has been assumed that adjustable' tap T1 is so positioned on resistor PDURI that current flowing through this resistor due to demandy units is suf cie'nt to dispatch a car, a positive potential is applied toV the grid of tube PTU with respect to its cathode of high' enough value to cause tube PTU to conduct current through the coil of summation up demand switch PDU of a value to cause this switch to operate.

Switch PDU, upon operation, engages contacts PDUI- in the dispatching circuits of Figure 3. Therefore, as' switch WBa operates, selecting car a for dispatching, it engages contacts WBZu, completing a circuit for the coil of up dispatch holding switch WBXa, the circuit extending' from supply line through contacts PDU1, WB'Za, the coil of switch WBXa, stationary contact SDM, brush SDBa and contacts C8251 to supply line Switch WB'Xt'zv `operates to initiate the automatic door closing operation (not shown) for car a and dispatching of the car inv ythe up direction.

Switch WBXa also engages its self holding contacts WBXla and separates contacts WBXS'a (Figure 4), interupting the current flow through resistor PDURI, thereby discontinuing the application of grid potential to tube PTU. Tube PTU then conducts insufficient current to maintain switch PDU in operated condition. Switch PDU releases, separating contacts PDUI (Fig` ure 3') in preparation for subsequent dispatching operations. Switch WBXa also separates contacts WBX4a, interrupting the circuit for the coil of switch WBa. Switch WBa releases to engage contacts WBSa, 'com-A pleting a circuit for the coil of switch VUR, the circuit extending from supply line -lthrough parallel contacts VBlb' and VBic, contacts VURI, the coil of switch VUR, contacts WBSQ, WBSb and WBSC to supply line Switch VUR operates to separate contacts VURl, deenergi'zing its coil and causing step-by-step countercjlocl wise rotary movement of its brushes VURBl-S. Brush VURBI 'engages stationary contact VURb, completing a circuit for the coil of switch WBb through contacts VBZb and WBX4b thereby transferring selection, `as the' next car to be dispatched, to c ar b. Switch WBbl o'perates to separate contacts WBSb, preventing other cars from being selected and engages contacts WBZ'ZJ, preparing 'the dispatching circuits for car b.

Switch WBXa also engages contacts WBXZa' (Figure l), completing a circuit through manual switch KSZa and contacts NT3a for the operating coil of starting and slowdown switch SRa. Switch SRa operates and latches in operated condition. Swith SRa, upon operation, engages contacts SRSa and, as the car and hois'tway doors reach closed position, hoistway door switch contacts DCO and car door switch contacts Gia close, complet circuit extending from supply line through contacts SRS'a, GIa, DCOu, the coil of switch Hav and emergency switch ESa to supply line Switch I-la opcratesto engage its self holding contactsI-la. lt -alsol engages contacts`H9a (Figure 2), completing a circuit for the coil of time delay switch NTa which operates,v without effect atl this time. In. addition, switch Ha' engages contacts H7a and H851` (Figure l), completing `a circuit for brake release coil BRa'. It also engages contacts Hlla and HIZa, and separates contacts Hwa, energizing the generator field windings GFa through contacts UPlGa and UPlla, causing cara tostart upward.

As a car starts upward from the lower dispatching landing, brush PUBa (Figure 3) engages stationary contact PUCZa, completing a circuit through contacts UPSa, NS2a and CS4a for the coil of up car position switch 2PIU. S-witch 2PIU operates to engage contacts ZPIUZ (Figure 6),. thereby illuminating lamp LU2 to indicate that an up traveling car is approaching the 2nd landing. Switch 2PIU also separates contacts ZPIUI (Figure 4), thereby isolating'the registered and predicted demand ahead of car al from affecting the up dispatching totalizer; Shortly after brush PUBa (Figure 3) engages stationary contact PUCZa, brush SDBa leaves stationary Contactl SDMa, interrupting thc circuit for the coil of switch WBXa. Switch WBXa releases, engaging contacts WBXSa (Figure 4) to prepare the up totalizer circuits of tube PTU for measuring the registered and predicted de'- mand ahead of selectedy car b.

Asl cari a leaves the lower dispatching landing, switch MLar (Figure l) is actuated by car movement, closing contacts MLla and opening contacts MLZa, without effect at this time. As car a continues moving upward toward the 2nd landing, brush PUBa (Figure 3) leaves stationary contact PUCla. This is without effect since a circuit through the coil of switch IPIU is maintained by means of brushes PUBb, PUBc in engagement with their respective stationary contacts PUClb, PUClc, indicating that a car set for up travel is still positioned at the lower dispatching landing.

It is believed it will be seen that as car a moves upward,l brush PUBa (Figure 3) first engages and then moves oft of stationary 4contacts PUCZa through PUC14a in succession, thereby causing switches 2PIU through 14PIU to operate and release in sequence. Switches 2PIU through 14PIU, as they thus operate and then release in'l sequence, first engage and then separate contacts ZPIUZ through 14PIU2 respectively (Figure 6i) thereby sequenw tially illuminating and then extinguishing lamps LU2 through LU14 to indicate continuously the position of car a as it travels upward.

Likewise, switches 2PIU through 14P1U, as they operate and release in sequence, separate and then engage their respective contacts ZPlUl through 14PIU1 (Figure 4) in sequence. As car a leaves the 2nd landing, switch 2PIU releases to reclose contacts 2PlU1, completing a circuit through resistor PDURI, the circuit extending fromV line B+ through resistor 2PUR, contacts ZPiUll, WBX3a, WBX3b, WXB3c and resistor PDURl to line B. This causes a certain amount of current ow through resistor PDURl. As car a leaves the 3rd landing, switch SPfliU releases to reclose contacts 3PIU1, inserting resistor SPUR for the 3rd landing in parallel with resistor 2PUR in the' up totalizing circuit, thereby increasing the current flow through resistor PDURI. In a similar manner, as -car a continues upward, resistors 4PUR through MPUR (not shown) are each inserted in parallel with resistor ZPUR in the up totalizing circuit, each increasing the current flow through resistor PDUR. Thus, as car a travels upw'ard, the predicted demand behind it and ahead of selected car b is totalized by the up dispatching demand totali'zer, for dispatching selected car b.

l As car leaves the 14th landing and contacts 14PIU1 (not shown) release to insert resistor MPUR (not shown) in the aforementioned up demand totalizing circuit, the

cetacei ohmic values of the predicted demand resistors connected in parallel provide a total of demand units. Thus the current through resistor PDURI is increased to a sufficient airiount to cause switch PDU to operate. Swith PDU, u'pn operation, engages contacts PDUI (Figure 3), inititing dispatching of selected car b and transferring selection from car b to car c, as was previously described for the up dispatch of car a and transfer of selection from car a to car b. v

Under the assumed conditions, suliicient demand also exists in the down direction to dispatch a car downward asv soon as it becomes selected for down dispatching.

This down demand is likewise due solely to the predicted demand from the landings and is totalizedby thedown dispatching demand totalizer, as follows: car c, positioned at the lower dispatching landing and set for upward travel, maintains contacts 1P1U1 (Figure 4) separated, as has been previously stated, preventing registered and predicted demand at the lower dispatching landing from af-i fecting the down dispatching demand totalizer. However, since no cars are presently traveling downward, a plurality of circuits is completed through resistor PDDRl in the down dispatching demand totalizer circuits, one such circuit extending from line B-lthrough predicted down demand resistor ZPDR, contacts 2PID1 to and including 16PID1, contacts WTXla, WTXlb, WTXlc and resistor PDDRI to line B, thereby causing a certain amount of current flow through resistor PDDRI. Similar circuits are completed through resistor PDDRI frornline B+' through resistors SPDR to and including resistor 16PDR tor the 3rd to 16th landings, respectively. Thus predicted down demand resistors of ohmic values to provide a total of 17 units of down demand are connected in parallel with each other and'in series withv resistor PDDRI. This causes suicient voltage to be applied to the grid of tube PTD with respect to its cathodeto cause it to conduct sufficient current through the coil of summation down demand switch PDD to cause this switch to operate and to maintain it in operated condition. Switch PDD, upon operation, engages contacts PDDI (Figure 3), preparing the down dispatching circuits to dispatch a car which becomes selected for down dispatching. ItY also separates contacts PDD2 (Figure l) in the highest car call circuits. As will be explained below, this allows an up traveling car to be selected below the upper dispatching landing.

The voltage applied across the anode-cathode circuit of gas diode tube TV is of sumcient magnitude to cause it to ionize and conduct, completing a circuit through resistor RTV. A potential drop is thus established across that resistor, which potential is applied across the coil of highest car call switch HCCa, maintaining it in operated condition. The coil circuit, for the car positioned at the lower dispatching landing, extends from the left side of resistor RTV through rectifier RWa, contacts PHCla, rectitier RXa, rectiiers RCB14a through RCBSa (not shown), rectitiers RCB4a through RCBZa, stationary contact CBla, brush BCBa, contacts UP12a, resistor RHCa, the coil of switch HCCa and over line B to the right side of resistor RTV. As car a travels upward, switch HCCa is maintained in operated condition by means of brush BCBa sequentially engaging stationary contacts CBZa through CB14a, until car a enters a top selection zone located above the 14th landing, the brush before running off a contact engaging the Contact ahead. As car a enters the top selection zone, brush BCBa rides oit of stationary contact .CB14a (not shown) for the 14th landing, interrupting the circuit through the coilv of .switch HCCa. The circuit is not maintained through contacts CBlSasince contacts PDDZa are separated, as has been stated previously. Switch HCCa releases to engage contacts HCCZct (Figure 2), for purposes to be explained later.

Switch HCCz also engages contacts HCCla (Figure 3'), completing a circuit` for the coil of available down car switchVTa, the circuit extending from supply line .GFa to decelerate car a.

`l through the coil of switch VTa, contacts UPld, HIUla, HlDla, HCCla, PHCZa and CSZrz to supplyv line Switch VTa operates to engage contacts VTZa, completing a circuit through parallel contacts NTZa and WTX3a and stationary 'contact VDRrz engaged by brush VDRB1 for the coiljof down selected car switch WTa, thereby selecting up traveling car a as the next car to be dispatched downward. Switch WTa operates to separate contacts WT3a, preventing energization of down notching switch VDRa and selection of any other car for dispatching downward.

Switch WTa also engages contacts WTla, completing a circuit for the coil of auxiliary down selected car switch WTXa, the circuit extending from supply line through contacts PDDI, WTla, the coil of switch WT'Xa, contacts UPla, HJUla, HJDla, HCOla, PHCZa and CSZa to supply line Switch W FXa operates to engage its self holding contacts WTXZa. This switch also separates contacts WTX'Sa, without effect, since they are presently short circuited by contacts NTZa which maintain the selection of car a, as the next car to be dispatched downward. Switch WTXav also engages contacts WTX4a (Figure 1), without effect, since they are short circuited by top landing switch contacts TLla and main landing switch contacts MLla and since contacts NTSa are presently separated. Contacts WTXla (Figure 4) also separate, interrupting the current ow through resistor PDDRI, thereby removing the positive potential on the grid of tube PTD which then conducts insufiicient current through the coil of switch PDD to maintain it in operated condition. Switch PDD releases, separating contacts PDDI (Figure 3) and engaging contacts PDDZa (Figure l), thereby preventing selection of another up traveling car below the upper dispatching landing.

Down selected car switch WTa, upon operating, also engages contacts WT 4a (Figure 2), completing a circuit for the coil of car reversal switch XHa to initiate the stopping and reversal ofv car a, as will be explained, the circuit extending through contacts HCCZa, HJU2a and Hl D241. Switch XHa operates to engage contacts XHZa, completing a self holding circuit `through contacts UPSa. Switch XHa, upon operation, also engages contacts XHZa (Figure 3), short circuiting contacts HJUla, HJDla and HCCla, thereby preventing demand above from affecting the selection of car a once the reversal operation is initiated, as will be explained later. In addition, this switch engages contacts XHla (Figure 1), completing a circuit for the release coil of switch SRa, as car a approaches the 15th landing, the circuit extending from supply line -lthrough the release coil of switch SRa, contacts XHla and UPSa and brush BUa in engagement with stationary contact CClSa, to supply line Switch SRa releases, separating contacts `SR4a, thereby inserting resistance in series with generator field winding Switch SRa also separates contacts SRSa, without ciect, since they are short circuited by contacts HSa and SSla. As car a arrives at the 15th landing, brush Ba engages stationary contact CC15a, completing a circuit for the coil of stopping switch SSa which operates, separating contacts SSla to interrupt the circuit for the coil of switch Ha. Switch Ha releases to separate contacts H7a and HSa, causing application of the brake, and separates contacts Hlla and H12a and, engages contacts 1111061, deenergizing generator iield windingGFa to stop the car yat the 15th landing.

Switch Ha also engages contacts H351 and H6a (Figure 2), completing a circuit through contacts DN6a for the release coil of up direction switch UPa and the operating coil of down direction switch DNa. Switch UPa releases land switch DNa operates, latching into operated conditerrupting the current flow through the release coil of switch`UPa andthe operating coil of switch DNa.`

15I Switchy UPa,` uponn releasing,` also separates contact ,y (Figure 3), interrupting the circuits through the.

nel i SRS@ Cmiiietin'gfa' @irc-uit. foi; the. Geil swish.' Hia. Switch... Heorsrates. i0. @ligase Contacts HM ansi H8@ re: leasingtrhc. brake, separatescontaots H-lQq, and, engages viundrng,- starting.V canadownward. car qzs'tarts dcwni taidffiii ihl 1511s lahaine? brush Ba fidesfifff 'Siatiaii com tact/CCIS@ interruptingy the circuity fory theA coil of.

NTawhichoperates, withoutfeiect at time.

It'maybe. noted that, as carv a arrives at tht-n.115trl1y lande. ing traveling upward, brush vPUBa (Figure 3). engages stfationaryfcontact BUClSn, coinpleting` a. circuit for; the ccil. of. switchy ISPIU which operates to: separate contacts. AISPiUl,` (Figure d). ingthe up ,dispatching demand totaliz/ler,V circuit. Switch 'LSRIUY also.l engages contacts ISRUZ; (Flinke,vk 61), causing` pcsition indicator I-.U15,.to illuminate to indicatejfthatangup caris. .approach-V ii the 15thk l'fandi'rug,` 4vAfs'4 car` stops. and-'reverses its direction of travell horn up tcA down at the ISthlanding, contaotsf (l-ig'ure. 3 ),y separate, interrupting the l cir; cuit'for they., coil of switch ISPIU and contacts yDN/lcr age, coinpl Hin :arcirvcuitvfor the coilofs witch ISRID liirfilsals Off @will PDB@ in engagement with Stationery contactV PDClSg. Switch]lPlUlreleasesto separate ccntacts 15mg-'2 in. the positioiiindicator. circuits offiigure. 6, thereby,extirigilishiiigflarnp4 LUlj. switch also agressifs'. CQiiiaziS/{lllii (Figure 4-)31'11 ihwpgdiraih: ing, dernaridftoitalilzcr circuits.l Switch 1512111. operates, iLQ. messa Oi/@taste '1511113.25 (Figure- 6), @twisting circuitfforllamp, LDlS-fwhichilluminates tot indicate that acanis aithewlSth;landingandlnow is set fortdownwardf' tr" a\l."cl.` separates contacts 1512'ID'1T(Eig.- ure..4), interrppti jthe.. dowrijdispatching d emandrtotalf izcrchan tori-vender iueltec'tuive,y demand resistorsfor landf aSedans;tierces/lila atfsiinstli@ .willdiiratshinsfdsfaadiotalizff i similar., to that, previously; dcscrihed` for cts H11 andHlfZldto encrgie the. generator field.'v

c, is, selected i for.,

' releases to engage contacts 4PID1 f ileschaintofi Figure 4. i0 maintain ineffective. mediana dw sister. isot'; suiiicient amount 'to 'in4 l ing'oflselccted carV c upward.

Assume QW that Cffir f1 has traveled' downward the 10th landing. Under such conditions brush E U U,- urs 3).-iSriIi1sHfsgs-msnt with: Staiismsry. contest-21212391011 (119i, shown), completing -a Qirsiiii. through Cantaga- Dlifia, NSM and; C54, fsf' the @Q il; Qfqswiish 1,01%1Df. Switch. lilPID Operates i0 Separate Cantatas; WRI-Dl; (119i. shown), interrupting the down' dispatching demand totaly,

resistors. i017- landinss 'below the 11th.- Ioweven. the. demand resistors for the 11th landing and aboyeare new` effective in the down totalizing circuit`` Thus, aplurality` 0f. Circuits from line B+ vthrugh predicted down; der. mand.. resistors M PDR through 16PDR is Completedthrough resistor PDDRI of the dow-n dispatching4 demandf totalirzer, thereby totalizing 8 demand units inthefdown.. direction.

Under suchl conditions there is insui'licient. down de?.

g` mand existing to cause. tube P TD toconduct enough curr..

rent to operate switch PDD and effect. selection; offf'up. traveling car b, for down dispatching, as ittenters the top selection zone. Thus car b is not reversed'andtdispatchcdc downward below the uppcrdispatching landing, aswas previously described forv car a,'but continuesA traveling. upward to. the. upper dispatching landing, whereit isl brought to. a stopand becomes conditionedfondowrb. ward travel,` in the manner earlier described*l for can` yarriving at the upper dispatching landing. `4

As car b arrives at the upper dispatching landing, brushv SDBb (Figure 3) engages stationary contact SDTIS, completing a circuit through contacts CSZb yfor thecoill off available down car switchVTb. Switch VTb operates t0 engage ccntacts VT2b, preparing a circuit for the coil; o fg down selectedvcar switch WTb.V Switch VTb also engages contact-s V-Tlb., completing a circuit-through contacts VDRI, WT3a, W T3b and WTS' for the'coil-l off downl notching switch VDR. Deenergigingof switch VDR by means oiits contacts VDRI causes counterclockwise rotary movement `oifbrushes VDRBI to VDRBS.

` As brush VDRB; engages stationary contact VDRb, a

down dcmandergists for it and,provided'that'the passen-4.

ger transfer` intervalprovidedibyswitch i liaseitpircd. Y W Y l Next assume that the passenger transfer interyal has,v expired,l In suchac'ase, switchNTbf triot shdwn.) rc; leases to'separate contacts N'I`2b, -vvithilteicct at time, and-to engage contacts"Nbinotvshown) preparirigthe star-ting cirfcAu-itlof car b. H A l f s I car a vciitiriue'sV traveling downward, theJh predicted,

doeii/ ii denandf resistors for" the landings behind ritz.

4PDR (not the dawn dispatching, demandtqtaiizer circsts-.ofilisiire Herstal@ Wititrreiicietisdswn demand.. resistors RDR tlrrgughQDi. Therefore, ias car avllleaves ltheAth:land:`

predicted dowi'idema'nd resistor 17 ing', 'a total of 13 such parallel cireuitsis completed through resistor PDDRI, the circuits extending from yline B+ through predicted down demand resistorsv 4PDR through 16PDR, connected in parallel and through contacts WTXla, WTXlb, WTXlc and resistor PDDRI to line B. For the weights in demand unitsA previously .as-v

sumed for the foregoing predicted down demand resistors, a total of l down demand units is thus totalized. This causes enough current to ow through resistor PDDRI to cause tube PTD tov conduct suicient current to operate summation down demand switch PDD. Switch PDD, upon operation, engages contacts PDDI (Figure 3), completing a circuit for the coil of switch WTXb, the circuit extending from supply line -ithrough contacts PDDI and WTlb, the coil of switch WTXb, stationary contact SDTb in rengagement with brush SDBb, and contacts `CSZb to supply line VSwitch WTXb operates to engage its self holding contacts WTX2b. Switch WTXb `also separatescontacts WTXSb, interrupting the circuit of switch WTb which releases, allowing another car to be selected for down ldispatching when available. It also engages contacts WTX4b (not shown) in fthe starting circuit of car b, thereby completing a circuit through contacts NT3b (not shown) for the operating coil of starting and slowdown switch SRb (not shown) to start car b downward in a similar manner to that previously described for car a.

Next assume that car b is positioned at the upper dispatching landing, Selected as the next car to be dispatched downward, that car a is traveling downward past the 14th landing, and that a down landing call for the 15th landing is registered 4behind next preceding car a. Under such conditions tube DH15 (Figure 2) conducts, establishing a voltage drop across resistor RD15. A circuit is thus completed from' the left side of resistor RD15 over cross-connecting wire. WDlS through rectifier RWDIS (Figure 4)landing call demand resistor ISRDR, contacts .15PID1,"16PID1,'WTX1a,WTX1b and WTXlc;l 'resistor PDDRII, and `over` line jB to the rightV side of resistorRDIS (Figure 2).. In this 'manner 5 units of registered down demand (the weight previously -given as representing a registered landing call) are yadded tothe totalizedrpredicted down demand units behind `next preceding car a.. Under such conditions, 'as car a leaves the 9thlanding traveling downward, predicted down demand resistor 9PDR (not shown) is inserted in vthe down dispatching demand totalizer circuits of Figure 4, increasing the total down demand units behind next preceding car a to 15, 10 of which are due to the predictedl down demand behind it and the remaining 5,o`f which are due to the down landing call registered `at the th landing. v herefore with 15 `down demand units totalized for selected car b, it is dispatched downward, as next preceding car a leaves the 9th landingV traveling down- 'ward, insteadrof waiting until car a travels past the 4th landing, as was described in the previous example.

Next assume that instead of` a down landing call-being Lregistered behind down traveling cara, as it travelspast the 14th landing, one or more car calls are registeredr in selected car b, as itis positioned at the upperY dispatching `lazrlding.v In' such a case, 5 units offdownpdemand" (the b is for the 3rd landing. This completes a circuit from the car call registering circuits of car b (not shown) over cross-connecting wire WC3b (Figure 5) through 'rectifier RET3b, they coil of down selected car, calll switch CKTb and contacts WTlZb vof the down selected l'car switch. Switch CKTbQAoperates to engage contacts CKTlb (Figure 4,), completing: a circuit through down 4demand totalizer resistor PDDRI, the circuit extending from line B+ through contacts CKTlb, resistor RCKb,V

contacts WTXla', WTXlb and WTX1c and resistor PDDRI to line B. Therefore, as next preceding car a leaves the 9th landing, traveling downward, a total of 15 down demand units, 5 due to the car call registered in selected car b and the other l0 due to predicted down demand behind car a, are totalized for selected car b, causing it to be dispatched downward, as was previously described.

By observation of the circuits of Figures 4 and 5, it will be seen that the registration of more than one car call in the selected car has the same effect as the registration of only one car call. Thus, with two or more car calls registered in the selected car, only 5 units of registered demand are added to the totalized predicted demand utilized to dispatch the selected car. In this manner passengers are prevented from interfering unduly with the dispatching of a selected car -by registering false car call demand. v

lNext assume the registration of a car call in selected car b, as it awaits down dispatching, in addition to the registration of a down landing call at the 15th landing behind down traveling car a. In such a case, l0 units of registered down demand, 5 `for the car call and 5 -for the landing call, are totalized with the predicted down demand behind the next preceding car a. Under such circumstances, selected car b is dispatched downward las next preceding car a leaves the 14th landing. Such is also the case, if it is assumed instead that two down landing calls, one for the 16th and one for the 15th landings, are registered behind down traveling car 1.

Next assume that, under conditions where a car call isin registration for selected car b, the realization of a totalized service demand for dispatching car b is delayed, say due to the number of stops being made by next preceding car a on its downward trip. This car call, as previously 'pointed out, causes operation of--switch CKTb. `Thus contacts CKT2b are engaged, completing a circuit for the coil of car call time switch ZKb, the circuit extending from line B+ through contacts CKTZb, the coil of switch ZKb andresistor RZKb to line B. Switch ZKb is delayed. in .operating by the t'une required for condenser QZKb, connected in parallel with its coil, to charge to a sufficient potential to cause itsroperation. When switch ZKb operates, it engages 4contacts ZKlb (Figure 3), completing a circuit for the coil of switch WTXb, the circuit extending from supply line through contacts ZKlb, the coil of switch WTXb, stationary contact SDTb in engagement with brush SDBb and contacts CSZb to supply line Thus, if the car call is registered longenough for the -delayed operation of switch ZKb to occur before there is suiiicient totalized registered and predicted demand to dispatch ear b, the operation of switch WTXb in response to such car call causes vthe dispatch of the ca r to take place without waiting on sufficient totalized'demand to arise. p Y e As has been previously pointedl out, a next preceding car, traveling in a given direction, interrupts the totalizer chain for that direction to render the registered and predicted demand for landings ahead of it ineffective for affecting the dispatching of a selected car at the dispatching landing behind it. For example, assume that car bV is at the proper dispatching landing, selected for down dispatching and next preceding car a is at say the 10th landing, traveling downward. Under such conditions, brush PDBa (Figure 3) is in engagement with 4stationary contact PDC10a (not shown), completing a circuit for the coil of switch 10PID (not shown) Switch `10PID is in operated condition, maintaining contacts 10PID1 (not shown) separated to interrupt 'the down dispatching demand totalizer chain in the circuits of Figure 4, thereby rendering registered and predicted down demand for landings below the 11th ineffective for aifect- 19 registered, it is not included in the totalized demand for dispatching car b and only 8 units of predicted down demand are totalized, an `amount insuilicient to velect dispatching.

Next assume that next preceding car a becomes loaded at 'thel 10th landing, to say 86% of capacity, to cause load switch LSa (Figure 2) to close, thereby completing a circuit for the coil of nonstop switch NSa. Switch NSa operates to separate contacts NSla, rendering ineffective the landing call pick-up circuits of car a which thereafter bypasses landing calls. Switch NSa also separates contacts NSZa (Figure 3), interrupting the circuit for the coil of switch IUPlD (not shown). Switch 10PID releases to engage contacts 10PlD1 (not shown) in the totalizer chain of Figure 4, thereby adding the registered and predicted down demand ahead of bypassing Car a to the 9 units of predicted down demand totalized behind it. Therefore, with next preceding car a bypassing landing calls, more than l down demand units are totalized for selected car b, causing it to be dispatched downward, as has been previously described.

In a similar manner, contacts NS2 (Figure 3) are effective to cause the predicted and registered up demand ahead of an uptraveling next preceding car which is bypassing up landing calls to bel added to the up demand behind it for dispatching a selected car from the lower dispatching landing.

Therefore, it is seen that a selected `car is dispatched when the total demand to which it is subject becomes, or exceeds, the assumed 15 `demand units of registered demand or predicted demand or any combinationy of them and, that under conditions where the next preceding car is bypassing landing calls, the registered demand and predicted demand ahead of that next preceding car and behind the next, next preceding car are included in such total demand `for dispatching the selected car.

Next assume that car c is at the lowerl dispatching Ilanding, and has been selected as the next car to be dispatched upward, while car a, the car previously dispatched upward, has traveled to the 10th landing. Further assume that car b. is traveling downward and sufcient down demand is totalized behind it to cause switch PDD to operate, thereby preparing theselecting and dispatching circuits `for reversing up traveling car a below lthe upper dispatching landing and dispatching it downward, as has been previously described. Under such conditions, as was pointed outgpreviously, switch HCCa (Figure l) is maintained in oper-ated condition by means of the voltage applied across its coil by the engagement of contacts PHCla until car a travels upward past the 14th landing to enter the top selection rone.` Thus, switch HCCa prevents car a from reversing below the 15th landing.

Next assume that a passenger enters next preceding ear a at the 10th landing and registers Ia car call for the 16th landing. Under such conditions, tube C16a conducts, establishing a voltage drop across resistor RC16a, thereby completing another circuit through brush BCBa in engagement with stationary contact CBlUa (not shown) yfor the coil of highest car call switch HCCa'. Thus, as car a travels upward, switch HCCa is maintained in operated condition 4by Vmeans of brush BCBa in engagement with stationary contacts CB-llal to CB16a until'the car call at the 16th landing is answered, thereby preventing the reversal of car ci as it enters the top Selection zone. As the stopping of car a at the 16th landing is initiated, canceling the car call, switch HCCa releases, engaging contacts I-ICClta (Figure 3) and HCCZa (Figure 2), thereby causing car a to reverse and be dispatched downward, as has been previously described, at

Y the landing of its highest call in the top selection zone.

yNext assume that instead of a car call being registered yin car a for the 16th landing, -a down landing call is registered by an intending passenger at the 16th landmg. Under such conditions, tube DH16 CQlld-llcts, es-

r20 c tablishing a'voltage drop across cathode resistor RD16, which voltage is applied, across the coil of highestv down landing call switch HIDa, the circuit extending from the left side of resistor RD16 through rectiiiers RED16,

REHlS to and including REHl, stationary contact DHHlQa in engagement with brush BDHHw, rectifier REHJa, contacts UP'14a, resistor RID, the coil of switch HJDa and over line Bk to the right side of resistor RD16` i Switch HlDa operates and is maintained in operated condition by means of brush BDHHa engaging stationary contacts DHI-111e to DHI-115e, as car a travels upward to the 16th landing to answer that down landing call. Switch HIDa, upon operation, separates contacts HJDla (Figure 3) Iand HIDZa (Figure 2), preventing up traveling car a from being selected for down dispatching, as it enters the top selection zone.

As car 1 approaches the 16th landing, brush BDHI-.Ia rides ott vof stationary contact DHHlSa, interrupting the circuit through the coil of highest down landing call switch HJDa. Switch HJDa releases to engage contacts HlDla (Figure 3), completing a circuit for switch VTa, thereby causing car a to be selected for down dispatching from the 16th landing, asV was previously described. The latter circuit extends lfrom supply line -ithrough the coil of switch VTa, contacts UP-l'a, HlUla, HlDla, HCCl, PHCZa and CSZa to supply line Switch yI-IJDa also eng-ages contacts HJDZa (Figure 2) to prepare the car reversal circuit for car a. As car a becomes so selected, switch WTa (Figure 3) operates, engaging contacts WT4a (Figure 2), thereby completing a circuit for the coil of car reversal switch kXHoz through contacts HCCZa, I-IIUZa and HIDZa. Switch XI-la operates to engage contacts XHla, rendering brush DPBa effective to pick up and cancel the down landing call at the 16th landing,

as the car approaches that landing. In additionswitch Xl-Ia, upon vroperation, initiates the stopping of car a -at the 16th landing andthe conditioning of it for downward travel, asf-has been previously described. -As has been previously described, at the expiration of the passenger transfer time interval car a is started downward.

Next assume that instead of a down landing call being registered at. the 16th landing, an up landing call is registered. .ln such afcase, tube UH16 conducts, completing a similar circuit Ifor the coil of highest up landing call switch HJUa (Figure 2). Switch HJUa' opcrates and is maintained in operated condition by means of brush BUHHaV in engagement with stationary contacts UHI-Illa to UHHlSa, as car a travels towards the 16th landing to answer the up landing call at that landing. Switch HIUa, upon operation, separates contacts HJUla (Figure 3) and HIUZa (Figure 2), thereby preventing car a from being selected for down dispatching, as it enters the top selection zone. Y

As car a answers the up landin-g call at the 16th landing and cancels thatv call, the circuit through the coil of highest up landing call switch HJUa is interrupted. Switch HIUa is delayed in -releasing for a certain time, illustrated for convenience as provided by the discharge of `condenser QlUa. into its coil. Condenser QJUa is selected so as to maintain switch HIsUa in operated condition until the expiration of a relatively short timel after the doors` have opened at the landing stop. In this manner enteringpassengers may `register car calls for landings above, causing the car to continue upward.` For example, assume that an entering passenger registers a rcar call for 'the 17th landing. In such a case'tube C17a (Figure l) conducts, causing switch HCCa to operate. Switch HCCa, upon operation, separates cont-acts HCCla (Figure 3) and HCCZa (Figure 2), thereby preventing reversal of c ar a and selection of car a for down dispatching, as has been previously described. Thus, at the exy termed preordained reversa.

landing. In ysuch a case, aftericondenser QJUa has discharged vsufficiently, switch HJUa releases to engage contacts HJUla (Figure 3) and HIUZ (Figure 2), causing car a to-be selected, reverseits idirection of travel to down and be dispatched downward, as has been described.' v

llt may be noted that, in the foregoing example, car c which is selected for dispatching from the lower dispatching landing is dispatched upward, as car a in traveling upward leaves the 14thl-anding, since 15 units of predicted up demand are then totalized behind'next preceding car a, as has been described. It may also be noted that, in the previous example, if a car call is registered insselected car c, as it waits to be dispatched upward, or an up 'landing call is registered behind next preceding car a,'say for the 6th landing, car c is dispatched as car a in traveling upward leaves the 9th landing instead of waiting until car aleaves the 14th landing.

" A car call which has been registered for a certain time in a selected car at the lower dispatching landing causes the car to be dispatched, regardless of the amount of up demand totalized for it, in the same manner as has been previously described for a long wait car call in aseIected car at the upper dispatching landing. For example, assume that car a is selected for dispatching upward and a car call is registered therein. In such a case, up selected car, car call switch CKBa (Figure operates, engaging contacts CKBla to complete a circuit for the coil of switch ZKa, which is delayedin operating for a certain time interval, as has been stated previously. At the expiration of that time interval, switch ZKa opcrates to engage contacts ZK2a (Figure 3), causing operation of switch WBXa and thus casing the car to be ,dispatchedfas v has been previously described.

z Ass'ume nowthat selected car a while awaiting dispatch becomes loaded to the previously assumed 50% of capacity. f .Under .such conditions," load dispatch switch LDSa `closes, completing, a circuit through contacts NTla and WBl, which are presently engaged, for t-he coil of up selected car load switch LDWa. Switch LDWa operates to engage contacts LDW'la (Figure 3), completing a circuit through .brush SDBa in engagement with stationary contact SDMa and through `contacts CSZa for the coil of switch WBXa. Switch WBXa operates to cause selected car a to be dispatched upward, as ypreviously described, even though sufficientV registered andpredicted demand to dispatch i-t'does not exist.

Therefore, it is seen that a car, selected as the next car to be dispatched from the lower dispatching landing,

-is immediately dispatched, under conditions where a car call is registered in it for a certain period or upon it becoming yloaded to a certain percentage of its capacity, 50% in this case, regardless of the amount of up registered and predicted demand totalized for it.

Under certain conditions of operation a selected car at the` lower dispatching landing may be conditioned to reverse at its highest call, an operation which .may be Such operation. is had under conditions where the car is dispatched on its upward trip before they totalized demand conditions .arise and'all previously registered landing calls have been caniceled for atleast a certain length of time, or if registered subsequent to thev expiration of that certain time, have not lbeen in registration' for apredetermined time. This `advance dispatch may be dueto a car callY having been in registration in the selected car for a certain period orto a car becoming loaded to a-certain percentage of capacity, as above set forth.

i such conditions, contacts `ZK3a and BLTIa (Figure 5) Yadvanced dispatching is initiated.

are engaged, completing a circuit through contacts UP6a for the coil of preordained reversal switch PHCa. Switch PHCa operates to engage its self holding contacts PHCSa. It also engages contacts PHCda (Figure 2), preparing a circuit for the coil of car reversal switch XHa. In -addition, it separates contacts PHCla (Figure 1), interrupting the circuit, previously traced, from the left side of resistor RTV through the coil of switch HCCa. However, switch HCCa is maintained in operated condition by the car call for the 3rd landing, previously assumed registered in selected car a. As selecter car a is advanced dispatched upward, it is conditioned to reverse at the landing of its highest call and then return to the lower dispatching landing, as will be explained below.

Car a travels upward to the 3rd landing, answers and cancels the car call, causing tube C3a to become extinguished, as Was previously described. As tube C3a is extinguished, the potential established across the coil of switch HCCa is removed, causing switch HCCa to release. This switch, upon releasing, engages contacts HCCZa (Figure 2) to complete a circuit through contacts PHC-la, HIUZa and HIDZa for the coil of switch XHa, causing car a to be set for downward travel and start back toward the lower dispatching landing, as was previously described. It may be noted, that a later registered landing call for a landing located above the position of car a, as it is traveling upward, causes switches HJUa or HJDa to operate, depending upon whether it is an up landing call or down landing call, as has been described. In such case, contacts HIUZa or HlD2a separate, -preventing the operation of switch XHa and the reversal of car a, until this landing call is answered. However, Vonce switch XHa operates to initiate the reversal operation, it engages contacts XH2a (Figure 3),v preventingcar a from responding to later lregistered calls above,` as has been previously stated.

As has been stated, this preordained reversal operation also takes place, if selected car a at the lowerdispatching landing is advanced dispatched due to it becoming loaded to a certain percentage of capacity, and the previously assumed landing call and totalized demand conditions exist. In such a case, switch LDWa (Figure 5 operates to cause the car to be advanced dispatched, as has been described previously. Swith LDWa, upon operation, also engages contacts LDWZa, completing a circuit through contacts UP6a and BLTla for the coil of switch PHCa. Switch PHCa operates to engage its self holding contacts PHCSa and conditions selected car a to reverse at its highest call, as hasY already been described.

y As has been stated, a car which is advanced dispatched upward is conditioned, upon being dispatched, to reverse at its highest call only under conditions where all previously existing landing calls have been canceled -for at least a certain time and if landing calls are registered after the expiration of that certain time, the latter have not been in' registration for a predetermined time before the In order to see the limiting effect of the registration of a landing call upon the advanced dispatching of a car, assume that priorto Y the car being advanced dispatched, a down landingfcall is registered for the 15th landing. Under such conditions, tube DHIS (Figure 2) is in conductingV condition, establishing a potential drop across cathode resistor RD15. A circuit is thus established from the left side of resistor RD15 through rectifier REDIS, resistor RLD, the coil 'of ydown landing call switch BLD and over line B to the To illustrate preordained reversal operation, assume Y .iirstthat a long wait car call for the 3rd landing'has right side of resistor RDIS. Switch BLD operates to engage contacts BLDl (Figure 5), completing a circuit for landing call time switch BLT. Switch BLT is delayed yin operating andalso in Areleasing for respective preldetermined times by the provision of a series circuit "comprising condenser QBL, resistor RBL, connected across its coil and by resistor RLT in series with its coil.

23 After a certain time delay, switch BLT operates. to sep@ arate contacts'BLTia, rendering switch PHCa ineffective for conditioning car a to reverse at its highest call.

Next assume that the call registered at the 151th landing is answered, causing tube DHllS (Figure 2) to be eX- tinguished, thereby removing the potential drop across resistor RD-ISv and causing switch BLD to release. Switch BLD, upon releasing, separates contacts ELDI (Figure 5), interrupting the circuit for the coil of switch BLT. Switch BLT is delayed `in releasing by the discharge of condenser QBL through its coil. A-fter a certain time interval, provided that no other up or down landing calls are registered, switch BLT releases, indicating that all previously registered landing calls have been answered for at least that certain time. Switch BLT, upon releasing, engages contacts BLTM, thereby preparing a circuit for the coil of preordained highest call reversal switch PHCa. It may be noted that switch BLT is similarly responsive to up `landing calls. This is accomplished by means of contacts BLU of up landing call switch BLU (Figure 2), which switch operates upon the registration of an up landing call and releases upon the cancellation of all up landing calls, in a manner similar to that described for switch BLD Ifor down landing calls.

Now assume that an up landing call or down landing call is registered subsequent to switch BLT releasing, thereby causing either contacts BLDIi or BLUI to engage and complete a circuit for the coil ot switch BLT. Switch BLT is delayed in reoperating for a predetermined period, as was previously stated. Therefore, under the assumed `conditions, all landing calls, up or down, have been answered for at least a certain period and a later registered landing call, up or down, has not been registered for at least a predetermined period. in such a case, upon car` a being advanced dispatched upward, switch PHCa operates to condition the car to reverse at its highest cal-l, as has been described. This switch, upon operation, also engages its self holding contacts PHCSa which short circuit contacts BLTla, thereby rendering subsequent operation of switch BLT due to later registered landing calls inetective.

It is thus seen that, if4 no landing calls are in registra tion for a predetermined time, a selected car `at the lower dispatching landing becomes loaded to say, 50% of its capacity or has a oar callV in registrationl for a predetermined period and later registered landing calls have not been registered for yat least a predetermined period, the selected car is advanced dispatched upward, preordained to reverse tat the landing of its highest call and then re.- turnV to the lower dispatching landing. If landing calls are already in registration for at least a predetermined period or if all previously existing landing calls have not been answered for at least a predetermined period before that lcar becomes loaded to the assumed 50% of capacity or before a car call has been registered'in it for a predef termined period, the selected car is advanced dispatched upward without being conditioned to reverse at the landing of its highest call. Thus the preordained reversal .operation takes place primarily during periods of incoming trac and an absence or" landing call demand.

If it is desired, any one of the cars may be taken out of group operation andV operated independently of the other cars. Also, it is to be understood, that one or more cars may be automatically removed from group operation in any suitable manner during periods of intermittent service and conversely may be automatically put into group operation, as demand increases. However, for simplicity, manual switches KSlitz` and KSZa have 4been provided to remove a car from` or restore it. to group operation. y

Assume that car a is removed from group operation by opening manual switch KSlla (Figure 2) and moving manual switch KS2@ (Figure l) to its upper position. The, operation of switch K525i insents starter button SBa and eld and brake switch contactsltIZain circuit with the.operating coil off switch SRa, rendering the staiting of oar a subjectV to starter button SBa `from within, the car. Also, the' opening Vof manual switch KSla. (Figure 2) causes switch CSa to release and eng-age contacts C830, thereby completing a circuit for the coil of nonstop switch NSa. Switch NSa operates to separate contacts NSla, disabling the landing call pick-up circuits -for car a to prevent car a from responding to landing calls. Y v YSwitch CSa also separates contacts CSZa (Figure 3), disabling the selecting yand dispatching` mechanism for selecting car a for dispatching. In addition, this switch separates contacts CS4a, disabling the car position circuits of car a, thereby preventing the position ofcar a from atecting the down dispatching and up dispatching demand totalizer circuits of Figure 4. Switch CSa also separates contacts CSla (Figure 4), inserting a portion of resistor PDDRl in the down demand totalizer circuits, increasing to a totalization of say 20 the units of predicted and registered down demand to effect the down dispatching of a selected car. Similarly, switch CSa separates contacts CSSa, inserting a pontion of resistor PDURI in the up demand totalizingv circuits, causing the up dispatching of a Iselected car to be eected upon the totalization of say 20 units of predicted and registered up demand. For purposes of fur-ther discussion it will be assumed that with one car removed from group operation, the number of units of demand for dispatching a selected car is increased to 20.

To illustrate such two oar operation, assume that car a is removed from service, that car b is positioned at the lower dispatching landing,V and is selected as the next car to be dispatched, and thatk car cis positioned at the upper dispatchinglanding and is selected as the next ear to be dispatched. Under such conditions,k brush PDBc (Figiure 3) is in engagement with stationary contactY PDC17c`, completing'a circuit for the coil of switch'17PlD, which switch is in operated condition, thereby maintaining contacts 17PID1 (Figure. 4) separated in the up dispatching totalizer chain. Also brush PUBb (Figure 3) is in .engagement with stationary contact PUClb, completing a circuit for the coil of switch IPIU, which switch is in operated condition, thereby maintaining its contacts 1PIU1 (Figure 4) separated in the down dispatching totalizer chain. Under such conditions, 17 units of predicted up demand are totalized for car b, which is insucient to cause it to be dispatched. Also, 17 units of predicted down demand are totalized for car c, an insuicient amount -to cause it to be dispatched. Therefore, both cars b and c remain standing `at their respective dispatching landings. Y

Next assume that a car call for :the 7th landing is registered in car b, adding 5 units of registered demand to the previously existing l7 units of predicted up demand. Thus, a total of 22 units of predicted and registered` up demand is totalized for car b, an amount sufficient to cause tube PTU to conduct enough current to operate switch PDU, causing car b to be dispatched upward, as

has been previously described. Car b in traveling upward answers the car call at the 7th landing and proceeds to the upper dispatching landing. Y

As car b= leaves the lower dispatching landing., brush PUBb (Figure 3) rides ofi of stationary contact PUClb, interrupting the circuit through the coil of switch 1PIU. Switch IPIU releases to engage contacts 1PIVU1 (Figure 4), introducing predicted up demand resistor IPUR, `for the irst landing, `in the down demand totalizer circuit, Y

thereby adding 4 additional units of predicted demand to the predicted down demand totalized' for car c. Thus, a total of 2l units of predicted down demandV is totalized for car c, an amotmt'sutlicient to cause tube'PTD to lconduct enough current Vto operate switch PDD, causing car-c to be dispatched downward, as has been previously described, and to proceed to the lower dispatching landing. Y i

i Therefore, it is seen that under the assumed conditions,

ata-14,6%

25 Y Y upon the registration of a car call in the selected car at the lower dispatching landing, it is dispatched upward, travels to the upper dispatching landing and parks there, becomingselected as the next car to be dispatched downward; while the selected car at the upper dispatching landing is dispatched downward, travels to the lower dispatching landing and parks there, becoming selected as the next car to be dispatched upward. l

It may be noted, that the registration of an up landing call also adds units of registered up demand to the 17 units of predicted up demand totalized for selected car b at the lower dispatching landing, resulting in its being dispatched, as has been just described for the registration of a car call in car b. Similarly, the registration of a down landing call or of a car call in selected car c at the upper dispatching landing adds 5 units of registered down demand to the 17 units of predicted down demand totalized for selected car c to effect the dispatching of car c downward.

If it is desired for a particular installation, a certain portion of the registered and predicted demand ahead of the car next preceding the selected car may be added to the registered and predicted demand behind such next preceding car for controlling the selected car. This may be accomplished by closing manual switches KSUa-c and KSDa-c in the demand totalizer circuits of Figure 4 thereby rendering brush pairs BPU, ZBPU and BPD, ZBPD effective for inserting Zener diodes ZDU in the up demand totalizer circuit and Zener diodes ZDD in the down `demand totalizer circuit, for cars a through c.

With reference to brush pair BPUa, ZBPUa and Zener diode ZDUa which are associated with car a in the up demand totalizer circuit, as car a" moves upward from the lower dispatching landing, brush BPUa engages stationary contact'PUZaand rides off of stationary contact PUla, while brush ZBPUa engages stationary contact PUla, Ythereby inserting the circuit comprising contacts UP7a, manual switch KSUa and Zener diode ZDUa in shunting relationship with contacts ZPIUI. As has been previously described, `as car a moves upward to the 2nd landing, brush PUBa (Figure 3) engages stationary contact PUCZa and rides off of stationary contact PUCla, causing switch ZPIU to operate and separate its contacts ZPIUI (Figure 4). However, contacts 2PIU1 are now shunted by Zener diode ZDUa, for purposes to be explained.

As car a moves upward from the 2nd landing, brush BPUa engages stationary contact PU3a and rides off of stationary contact PUZa, while brush ZBPUa Vengages stationary contact PUZa and rides ot of stationary contact PUla, thereby inserting the shunting circuit across contacts 3PIU1, while removing it from across contacts ZPIUL At the same time, brush PUBa (Figure 3) engages stationary contact PUC3a and rides off of stationary contact PUCZa, causing switch 3PIU`to operate and switch ZPIU to release, as has been described, thereby separating contacts 3PIU1 (Figure 4) and engaging contacts 2P1U1, respectively. As car a continues upward, contacts 4PIU1 through 16PIU1 and 17PID1 are likewise separated and then engaged in sequence, each pair of contacts in the up demand totalizer chainwhile in separated condition being shunted by Zener diode ZDUa. Similarly, if it is assumed that car a is dispatched downward from the upper dispatching landing, as it travels downward, contacts 16PID1 through 2PID1 and 1PIU1 are likewise sequentially separated and engaged. However, as each pair of contacts in the down demand totalizer chain is thus separated, brush pair BPDa, ZBPDa inserts the circuit comprising Zener diode ZDDa, manual switch KSDa and contacts DNSa across the separated contacts. Similar shunting circuits are provided for cars b and c.

1 Zener diodes ZDU, ZDD in the aforementioned shunting circuits are circuit elements which when in conducting condition Yinherently have; avconstant' voltage `drop Y vl26 across their terminals while conducting various inverse currents. Each of these diodes, as it is connected in shunting relationship to the rst pair ofcontacts in the totalizer chain, has a potential applied across its terminals of sufficient magnitude to cause itto conduct a certain inverse current. With proper selection of the Zener diodes, the magnitude of this inverse current is dependent upon and varies with the ohmic value of the demand resistors which represent the registered and predicted demand at landings ahead of a next preceding car for a given direction of travel and which are connected in parallel with eachother and in series with the Zener diode associated with such next preceding car for that direction of travel. This inverse current flows through that Zener diode and through the totalizer resistor (PDURI, PDDRI) associated with that direction of travel. Such current is additive to the current flow due to demand resistors connected in parallel in that totalizer circuit, whose ohmic values represent the registered and predicted demand in units totalized behind the next preceding car. As the demand ahead of the next preceding car increases, additional demand resistors are connected in the parallel circuit which is connected in series with the Zener diode associated with that car causing the inverse current flow through that diode to increase. Thus, by proper selection of these Zener diodes (ZDD, ZDU) in relation to the other circuit parameters in the totalizer circuits, a predetermined portion of the demand ahead of the next preceding car is added to the demand behind it to effect dispatching of the selected car.

Assume that, for vpurposes of this embodiment, the Zener diodes in the respective shunting circuits for cars a through c have been'seleeted soY as to allow one third of the registered and predicted demand ahead ofthe next preceding carY to be added to the demand behind it.

Also assume that l5 units of totalized demand are required to initiate dispatching of the selected car.

To illustrate the dispatching of a selected car bythe summation of the predicted and registered demand behind the next preceding car and a certain portion of the predicted and registered demand ahead of that next preceding car (in this case one third), assume that car a has been dispatched upward and is presently at the 3rd landing and that car c has arrived at the upper dispatching landing and is set for down travel. Further assume that car b is the next car selected to be dispatched upward. Under such conditions, contacts 3PIU1 (Figure 4) are separated and brush BPUa is in engagement with stationary contact PUSa, while brush ZBPUa is in engagement with stationary contact PUZa, inserting Zener diode ZDU@ in shunting relationship with'- separated contacts 3PIU1. Further assume that up landing calls are registered at the 10th and 12th landing. Under such conditions, 2 units of up demand, due tothe predicted up demand established for the 2nd. landing, exist behind next preceding car a and 25 units of up demand exist ahead of it, 10 vdue to registered up landing calls` at 5 units each and 15 due to predicted demand resistors SPUR through 16PUR connected in parallel. Therefore, Zener diode ZDUa conducts a certain current corresponding to 8.33 demand lunits or onethird of theregistered and predicted demand ahead of next preceding car a. In such a case, the total demand effective in the up totalizer circuit is 10.33 units, 8.3%V units due to demand ahead and 2 units due to de- -rnand behind.

Next assume that an up landing call .is registered for the 15th landing, adding another 5 units of up demand ahead of next preceding car a. Under such conditions, Zener diode ZDUa conducts a certain current corresponding to l0 units of demand around separated contacts 3PIU1 into the up demand totalizer circuit. Therefore, 12 units of up demand are presently totalized ahead of selected car b, an amount insuicient to initiate dispatching of selected car b. Next `assume that an. up landing callV is registered at the 2nd landing, adding Sunits of 

